The present invention relates to medical devices. More particularly, the invention relates to a removable vena cava clot filter that can be percutaneously placed in and removed from the vena cava of a patient.
A need for filtering devices arises in trauma patients, orthopedic surgery patients, neurosurgery patients, or in patients having medical conditions requiring bed rest or non-movement. During such medical conditions, filtering devices are inserted to prevent thromboses in the peripheral vasculature of patients when thrombi break away from the vessel wall, risking downstream embolism or embolization. For example, depending on the size, such thrombi pose a serious risk of pulmonary embolism wherein blood clots migrate from the peripheral vasculature through the heart and into the lungs.
The benefits of a vena cava filter have been well established. After deployment of a filter in a patient, proliferating intimal cells begin to accumulate around filter struts that contact the wall of the vessel. After a length of time, such ingrowth poses difficulties for removal of the filter. In addition, typical filter deployment and retrieval are directionally dependent. For example, filters inserted using a femoral approach may require the retrieval to take place through a jugular approach. A vena cava filter that can be easily retrieved independent of the orientation of the filter deployment within the vessel